Radial-flow turbine



March 25, 1924. 1,488,117

H. T. HERR RADIAL FLOW TURBINE Filed Sept. 30. 1921 F17 INVENTOR ATTORNEY v Fatented iidar. 25, iea a.

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HERBERT T. HERB, F MERION, PENNSYLVANIA, ASSIGNOR 'IO WESTINGHOUSE ELEC- TRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIEL.

RADIAL-FLOW TURBINE.

Application filed. September so, 1921. Serial a. coarse.

To all whom it may concern:

'Be it known that I. HERBERT T. HERR, a citizen of the United States, and a resident of Merion, in the county of Montgomcry and State of Pennsylvania, have invented a new and useful Improvement in Radial-Flow Turbines, of which the followin is a specification.

y invention relates to elastic-fluid. tur- W bines, and more particularly to those of the double-rotation type, and it has foran object to provide low-pressure blading therefor which shall be simple in design and be capable of handling large volumes of'low- 15 pressure elastic fluid efficiently.

This and other objects are attained by apparatus embodying the features herein described and illustrated in theaccompan ing drawings, forming a part of this app iceac tion, in which Fig. 1 is a view, partly in section and partly in elevation, of a doublerotation type of turbine showin my improved blading applied thereto; Figs. 2 and 3, are sections taken along the lines ill-H 255 and HTHI, respectively, of Fig. 1; Fig. 4 is a detail view showing a modified form of my improved blading; Figs. 5 and 6 are sectional views taken along the lines of V-V and Vl[VT of Fig. 4; Fig. 7 is a at detail sectional view of a further modified type of blading; and Fig. 8 shows a further modified form of my improved blading.

Turbines of the double-rotation or Ljungstrom type, while advantageous in many as we s, are limited in practical construction an operation to relatively small capacities. It has been proposed to improve the elasticfluid-handling capacity of a turbine of this type by providing the rotors with an in= an tricate system of interleaving blades having parallel expanding elastic-fluid passages therein; however, this type of-bladin is subject to high centrifugal stresses an is also costly to make, to install, and to mamas tain in o eration.

Accordmgly, it is a detailed object of my invention to provide low-pressure bladin for a double-rotation turbine which she have adequate discharge area with small to leaving angles, whereby high blade eficiency may be had. I accomplish this result by providin blades which have straight mlet edges and outlet edges which are materially greater in extent than the inlet edgm. The

ends of the outlet edges approach the ends of the inlet edges but at intermediate points the edges are suitably spaced apart so as to provide for the materially greater extent of the discharge edges as compared wlth the inlet edges. In so far as my present invention is concerned, the particular shape of the blade is immaterial so long as the principle is conserved of providing discharge edges of materially greater extent than the inlet edges, whereby adequate discharge area with small leaving angles are provided. Therefore, since my improved form of low-pressure blading is simple in construction and highly efficient in opera-. tion, it is possible by utilizing my new type of blade, to build economically a double-rotation turbine of large capacity and high efliciency.

Referring now to the drawings for a more detailed description of my invention, I show an elastic-fluid turbine 10 of the doublerotation type, provided with a suitable casing 11 having oppositely rotating rotors 12 arranged therein and secured to the shafts 13 journaled in any suitable manner in the casing and provided With suitable acking devices 14 between the casing an the shafts to prevent escape of elastic fluid from the interior of the casing around the shafts to the atmosphere. The oppositely rotating rotors 12 have concentric drums of inter caving blades 15 secured thereto alternately in any suitable manner, as, for example, by the expansion rings 16.

Elastic fluid or steam is supplied by means of suitable conduits 17 in communication with the space 18 within the innermost drum of blades 15. As shown, the conduits 17 communicate with chambers 19' which communicate with the central space 18 by means of suitable passageways 20 provided in the rotor elements 12.

Labyrinth packing 21 of the radial type is interposed between the rotor elements 12 and the walls of the casing 11 in order to prevent the escape of elastic fluid directly to the exhaust chamber 22 as well as to assist in balancing the thrust imposed upon the rotor elements.

My im roved blading, asshown in Fi 1-7, inc usive, comprises a circumferential row of blades 25 secured to the rings 26 in any suitable manner, and one of the rings is lltlt) adapted to be connected to one or the rotor elements 12 by any suitable means, for

example, by an expansion ring 27.

The blades 25 are substantially -semi-cir cular in outline, that is, they are provided with straight inlet edges 28, and with curved outlet edges 29, whereby the outlet edges may be made substantially longer than the inlet edges, which is advantageous for reasons hereinafter stated.

The blades 25 are suitably shaped or curved to provide for the discharge of elas tic fluid, both radially and laterally, as

indicated by the arrows in Fig. 1; and as the leaving edges are substantially longer than the inlet edges, adequate discharge area may be provided for the discharge of elastic fluid at small angles. In Figs. 1,2, and

3, I show the blade 25 as being convexly curved and provided with a substantially straight inlet edge 28. In Figs. 4, 5, and

6, I show a curved hook-like portion 30 approximately concentric with the curved edge 29 and encompassing a substantially radial semi-circular portion 31. One of the advantages of the construction shown in Figures 4, 5, and 6, is that the mass of each blade may be so disposed as to have the center of gravity located substantially mid-way of the thickness of the inner portion 31, whereby unbalanced centrifugal bending moments are substantially avoided.

The structure shown in Figs. 4, 5, and 6, is subject to afurther modification in that, as shown in Fig. 7, the outlet portions 32 of the trough portions 33 may be so designed as to define withv one another distinct diverging elastic fluid passageways 34, having throat portions 35. This construction pro vides for a greater range of expansion.

In Fig. 8, I show a further design of blading, whereby the extent of the leaving edge may be further increased. In this view, I show an elongated blade 37 having a straight inlet edge 38 and lateral and peripheral discharge edges 39 and 40. The

blade 37 may be shaped in either of the ways disclosed in-connection with Figs. 1 to 7, inclusive, in order to provide for small leaving angles. Furthermore, the blades may be so shaped and the discharge angles of the edges 39 and 40 may be so varied as to secure eflicient abstraction of energy from the elastic fluid while, at the same time, maintaining high capacity for handling large volumes. The blades 37 are firmly supported by side rings 41, and one of the latter is fastened to one of the rotor elements' 12 by means of a suitable expansion ring 42.

While I have shown and described blades havin semi-circular and elongated outlines, it wil be obvious to those skilled in the art that any other suitable outline migh be selected so long as the principle of my inve'ntion is conserved, namely, .to provide a blade of such; an outline as to have an outlet or discharge edge which is much tion of my invention will be evident. Elastic fluid is expanded radially between the interleaving b ades of the oppositely rotating rotors 12 in. a well-known manner and is discharged from the outer drum of blades 15 for entry between the inlet edges 28 or 38 of the semi-circular blades 25 or the elongated blades 37. The elastic fluid is expanded between the blades, and the latter are so shaped, in connection with the curved outlet edges,'as to provide for the expansion and discharge of elastic fluid both radially and laterally, as indicated'by the arrows in Figs. 1 and 8. As the outlet or discharge edges of the blades 25 and-37 are muchlonger than the inlet edges 28 and 38, respectively, adequate discharge area may be provided for the elastic fluid at small angles, whereby the blading is capable of handling large volumes of elastic fluid with high efficiency. From the foregoing, it will be seen that I have devised an outer drum of blading for a turbine of the double-rotation type which is capable of handling large volumes of low-pressure elastic fluid with high blade efliciency, whereby turbines of the type referred to may be constructed in large sizes to operate with high economy.

WhileI have shown my invention'in but three. forms, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications, without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as specifically set forth in the appended claims. I a

What I claimisz- 1. In an elastic-fluid nation of oppositely-rotating rotors having concentric rows of intercaving blades throu h which elastic fluid flows in a radial direction and a last row of moving blades having discharge edges so shaped as to pro-' turbine, the comhivide for the discharge of elastic. fluid both radially and with bi-lateral components of direction.

2. In an elastic-fluid turbine, the combination of oppositely-rotatin rotors having concentric rows of intercaving blades throu h which elastic fluid flows. in a radial direction and a last row of blades, each of which has a straight inlet edge and an outlet edge which ap roaches the ends of the inlet edge but issuitably spaced from the inlet edge at points between the ends of the latter, whereby an outlet edge of substantially greater extent than the .inlet provided.

3. In an elastic-fluid turbine, the combination of a pair of oppositely rotating rotors having concentric drums of moving blades through which elastic fluid flows in a radial direction and a last row of blades having straight inlet edges and non-parallel outlet edges which approach the ends of the inlet edges.

4. In a radial-flow,

edge may be elastic-fluid turbine, the combination of oppositelydisposed double rotation rotors having concentric rows of inter-leaving blades and a last row of blades having inlet edges substantially parallel to the turbine axis and lateral and peripheral discharge edges which approach the ends of the inlet edges.

5. In an elastic-fluid turbine, the combination of oppositely-rotating rotors hav ing concentric rows of inter-leaving blades through which elastic fluid flows in a radial direction and a last row of blades having curved outlet edges and being so shaped as to provide for the discharge of elastic fluid at small angles radially and with bi-lateral components of direction.

6. In an elastic-fluid turbine, the combination of a pair of oppositely rotatable rotors with interleaving blades carried thereby and a last row of blades of substantially semi-circular outline carried by one of the rotors.

7 In a turbine, the combination of a pair of oppositely rotatable rotors having a plurality of concentric interleaving rows of blades carried thereby and a last row of blades having outlet edges, which approach the ends of the inlet edges and which are substantially greater in extent than the inlet edges, whereby adequate discharge area With small leaving angles may be provided.

8. In a turbine, the combination of a pair of oppositely rotatable rotors with concentric rows of interleaving blades carried thereby and a last row of blades having straight inlet edges and curved outlet edges, whereby adequate discharge area at small angles radially and with bi-lateral components of direction may be vprovided, holding rings secured to the ends of the blades, and means for connecting one of the rings to one of the rotors.

9. In an elastic-fluid turbine, the combination of oppositely-rotating rotors having concentric rows of inter-leaving blades through which elastic fluid flows in a radial direction and a row of blades each of which is of segmental contour having the straight portion as the inlet edge and the curved portion as the outlet edge.

10. In an elastic-fluid turbine, the combination of a pair of oppositely-rotating rotors having concentric drums of moving blades through which elastic fluid flows in a radial direction and a row of blades so curved as to expand and to discharge elastic fluid arcuately.

In testimony whereof, I have hereunto subscribed my name this 23rd day of September, 1921.

HERBERT T. HERR. 

